Tampermonkey userscript to calculate and show "meta scores" for each combo on mk8dxbuilder.com

mk8dxbuilder_meta_scores.user.js

// ==UserScript==
// @name         mk8dxbuilder meta scores
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  calculate and show meta scores for each combo
// @author       chrod64
// @match        https://mk8dxbuilder.com/
// @icon         https://www.google.com/s2/favicons?sz=64&domain=mk8dxbuilder.com
// @grant        none
// ==/UserScript==

// From my gist: https://gist.github.com/m-byte918/98e47d96102eee4dd3b166ee684d68ca

(function() {
    // Ordered from least -> most important
    // See: https://strawpoll.com/polls/B2ZBEWz5zgJ/results
    const stats = [ "traction", "invincibility", "handling", "weight", "acceleration", "speed", "miniturbo" ];

    // nth triangle number - https://math.stackexchange.com/questions/593318/factorial-but-with-addition
    const n = stats.length;
    const statWeightScalar = 1 / ((n**2 + n) / 2);

    const statWeights = { };
    for (let i = 0; i < n; ++i) {
        statWeights[stats[i]] = (i + 1) * statWeightScalar;
    }

    // Different weights for each speed/handling type, see: https://vikemk.com/posts/mk8dx-combos
    // and https://docs.google.com/spreadsheets/d/1idLq3OYkEjRI0U64LCLxVY-GvdhRPgO75KZUPS4m70o/edit#gid=0
    statWeights.speed = {
        ground: statWeights.speed * 0.737,
        antigrav: statWeights.speed * 0.181,
        air: statWeights.speed * 0.056,
        water: statWeights.speed * 0.026,
    };
    statWeights.handling = {
        ground: statWeights.handling * 0.737,
        antigrav: statWeights.handling * 0.181,
        air: statWeights.handling * 0.056,
        water: statWeights.handling * 0.026,
    };

    function calcMetaScore(buildElem) {
        const statsUnparsed = buildElem.getElementsByClassName("loading-container-def");
        const stats = []; // Stats is an array containing each stat in order (top-to-bottom) on mk8dxbuilder

        for (let stat of statsUnparsed) {
            stat = parseFloat(stat.lastElementChild.getAttribute("title").split(": ")[1]);
            stats.push(stat);
        }

        const metaScore = stats[0] * statWeights.speed.ground +
               stats[1] * statWeights.speed.water +
               stats[2] * statWeights.speed.air +
               stats[3] * statWeights.speed.antigrav +
               stats[4] * statWeights.acceleration +

               // Weight is no longer floored to the nearest whole number as of version 2.1.0.
               // see https://media.discordapp.net/attachments/905144339385159783/1140484171165356093/gKbcfRh.png
               stats[5] * statWeights.weight + 

               stats[6] * statWeights.handling.ground +
               stats[7] * statWeights.handling.water +
               stats[8] * statWeights.handling.air +
               stats[9] * statWeights.handling.antigrav +
               stats[10] * statWeights.traction +
               stats[11] * statWeights.miniturbo +
               stats[12] * statWeights.invincibility;

        buildElem.lastElementChild.innerHTML = "Meta Score: " + metaScore.toFixed(3);
    }

    // Just calculate it on every click
    document.querySelectorAll('*').forEach(element => element.addEventListener('click', e => {
        const build1Div = document.getElementById("regionBuild1").lastElementChild;
        const build2Div = document.getElementById("regionBuild2").lastElementChild;
        const build3Div = document.getElementById("regionBuild3").lastElementChild;

        if (build1Div.lastElementChild.nodeName !== "H4") {
            build1Div.innerHTML += "<br><h4>Meta Score: 0</h4>";
            build2Div.innerHTML += "<br><h4>Meta Score: 0</h4>";
            build3Div.innerHTML += "<br><h4>Meta Score: 0</h4>";
        } else {
            // Update
            calcMetaScore(build1Div);
            calcMetaScore(build2Div);
            calcMetaScore(build3Div);
        }
    }));
})();